Efficient solar thermal storage of foamy bamboo charcoal-based composite phase change materials

Abstract

Solid/liquid phase change materials (PCMs) with high phase change latent heat have been widely used in thermal energy storage in recent years, but their own disadvantages such as poor light-absorbing capacity, easy leakage, and low thermal conductivity seriously limit their practical use in solar thermal storage applications. In this study, a series of biomass-derived porous carbons (CB400, CB550, and CB700) were synthesized by combining the template method with the activation method through high-temperature carbonization using bamboo as raw material and Ca(OH)2 as precursor. 1-octadecanol (OC) is selected as the PCM, and four different composite photothermal phase change thermal storage materials (CB550-85, CB550-80, CB550-75 and CB550-70) were prepared by using CB550 as the photosensitizer and support material. The phase change enthalpy of CB550-85 with 85 wt% OC content was 299.8 J/g, the thermal conductivity of CB550-70 with 70 wt% OC content was 0.71 W·m−1·K−1, which is 184 % higher than that of 1-octadecanol. CB550-OC has good thermal and shape stability, excellent solar energy absorption capacity and photothermal conversion performance. This study provides a new technological pathway for the utilization of biomass. CB550-OC has a broad application prospect in the field of solar thermal utilization and thermal energy storage.